Electronic apparatus using fuel cell assembly

ABSTRACT

In this invention, a fuel cell assembly and an air channel for supplying air to the fuel cell assembly are arranged in a display unit of an electronic apparatus. A drain hole for draining water produced by the fuel cell assembly is formed in a side surface of the display unit. When a drain tool is connected to the drain hole and the electronic apparatus is in the OFF state, the operation mode switches to a fuel cell assembly mode for using the fuel cell assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2000-233136, filed Aug.1, 2000, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an electronic apparatus using afuel cell assembly as a power supply and, more particularly, to apersonal computer using a fuel cell assembly of a type that directlyoxidizes methanol.

[0004] 2. Description of the Related Art

[0005] Various types of personal computers using fuel cell assembly havebeen proposed. In a personal computer using a conventional fuel cellassembly, the fuel cell assembly is mounted in the personal computerbody.

[0006] Such a personal computer is disclosed in, for example, Jpn. Pat.Appln. KOKAI Publication No. 9-213359. The fuel cell assembly disclosedin Jpn. Pat. Appln. KOKAI Publication No. 9-213359 uses ahydrogen-absorbing metal.

[0007] In addition to a fuel cell assembly using a hydrogen-absorbingalloy, a DMFC (a fuel cell assembly designed to directly oxidizemethanol) has been devised. Such a DMFC is disclosed in, for example,Japanese Patent Application No. 10-278759filed by the present applicant.A DMFC does not require so-called auxiliary equipment for a fuel system,and hence has no movable mechanical portion. For this reason, the DMFCis readily made compact and lightweight and can be optimally used as apower supply for a notebook personal computer (to be referred to as anotebook PC hereinafter)

[0008] If, however, a DMFC is designed not to have a stacked cellstructure so as to manufacture the cell at a low cost, air supplied tothe cell relies on diffusion and convection. As a consequence, to supplypower required for a current notebook PC, the DMFC has an excessivelylarge area. Even if the performance of a DMFC improves to, for example,45 mW/cm², the cell needs to have an area of 1,000 cm² to supply 45 W.It is therefore the first challenge to incorporate a fuel cell assemblypanel having the largest possible area into a notebook PC having limitedoutside dimensions and improve ventilation of the fuel cell assemblypanel without using any ventilating fan.

[0009] The biggest merit in using a fuel cell assembly for a portableapparatus is that the apparatus can be used substantially unlimitedwhile being out as long as a fuel is carried. However, the power thatcan be extracted from the fuel cell assembly is limited. If a highpriority is to be given to the long-term use of a personal computer evenat the expense of performance, the personal computer needs to beoperated with a great restriction on power consumption. However, presentnotebook PCs are not designed to operate on the power that can beextracted from a fuel cell assembly. The second challenge is thereforeto provide a notebook PC which can be used with a restriction imposed onpower consumption without making the user misunderstand.

[0010] A fuel cell assembly essentially produces water. In general, thiswater is evaporated by using heat generated in the computer. It is,however, inevitable that evaporated steam is liquefied in the housing ofthe personal computer or the like, depending on environmentalconditions. Designing a personal computer to prevent this water fromentering the computer contradicts the requirements of heat dissipation,ventilation, and the like.

[0011] In a conventional personal computer, a fuel cell assembly isplaced in the computer, and water produced by the fuel cell assemblyenters the computer, resulting in a failure in the computer.

BRIEF SUMMARY OF THE INVENTION

[0012] The present invention has been made in consideration of the abovesituation, and has as its object to provide an electronic apparatuswhich can incorporate a fuel cell assembly panel having a large area andprovide good ventilation for the fuel cell assembly panel.

[0013] It is another object of the present invention to provide anelectronic apparatus which can normally operate even on low powerobtained from a fuel cell assembly.

[0014] In general, a notebook PC has a display unit which is rotatablymounted on the main body, and is usually rotated to nearly vertical whenused. Since the display unit generally has an area near the upper limitwithin the notebook PC, it is reasonable that a fuel cell assembly panelrequiring a large area is placed on the rear surface of the displayunit. Since the display panel is often used at an angle near the rightangle, convection effectively provides ventilation. Therefore, byplacing the fuel cell assembly panel on the rear surface of the displayunit, the first challenge can be achieved. Such an arrangement hasalready been indicated in H. L. Maynard et al., “Miniaturized Fuel cellassembly for Portable Power”, 2nd Annual Advances in R&D for thecommercialization of Small Fuel Cells and Battery Technologies for usein Portable Applications (Apr. 26-28, 2000).

[0015] The efficiency of a fuel cell assembly is generally high at ahigh temperature, and the fuel cell assembly generates heat equivalentto output power during operation. On the other hand, an LCD panel widelyused for a display unit is susceptible to heat.

[0016] Since the cathode side of a fuel cell assembly panel requiresoxygen, outside air is supplied thereto. Forming an air channel forsupplying outside air on the LCD side will facilitate heat insulationbetween the fuel cell assembly and the LCD panel. This makes it possibleto attain a reduction in cost. This is because, the temperature of theair channel is considerably lower than the temperature of the fuel cellassembly panel itself.

[0017] According to the first aspect of the present invention, there isprovided an electronic apparatus comprising an electronic apparatusbody, and a display unit rotatably mounted on the electronic apparatusbody, wherein a fuel cell assembly for supplying power to the electronicapparatus and an air channel for supplying air to the fuel cell assemblyare arranged in the display unit.

[0018] According to the second aspect of the present invention, there isprovided a method of driving an electronic apparatus including anelectronic apparatus body, and a display unit rotatably mounted on theelectronic apparatus body, the display unit having a fuel cell assemblyfor supplying power to the electronic apparatus and a drain hole fordraining water produced by the fuel cell assembly, comprising the stepsof switching to a fuel cell assembly mode for using the fuel cellassembly, when it is detected that a tool for collecting water producedby the fuel cell assembly is connected to the drain hole, and a powersupply of the electronic apparatus is in an OFF state, and executing apower supply ON sequence unique to the fuel cell assembly mode when thepower supply of the electronic apparatus is turned on, and the outputpower of the fuel cell assembly reaches a predetermined value.

[0019] According to the present invention, the operation mode can beautomatically switched to the fuel cell assembly mode only when a toolfor collecting water produced by the fuel cell assembly is connected tothe drain hole, and the electronic apparatus is in the OFF state. Thisprevents the user from making erroneous operation mode setting.

[0020] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0021] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently embodimentsof the invention, and together with the general description given aboveand the detailed description of the embodiments given below, serve toexplain the principles of the invention.

[0022]FIG. 1 is a perspective view of a notebook PC according to anembodiment of the present invention;

[0023]FIG. 2 is a sectional view taken along a line X-X′ of the displayunit of the notebook PC;

[0024]FIG. 3 is a block diagram of the notebook PC according to anembodiment of the present invention;

[0025]FIG. 4 is a flow chart for explaining the first example of a fuelcell assembly mode;

[0026]FIG. 5 is a flow chart for explaining the second example of thefuel cell assembly mode;

[0027]FIG. 6 is a flow chart for explaining the third example of thefuel cell assembly mode;

[0028]FIG. 7 is a state diagram for explaining mode switching of thenotebook PC according to this embodiment; and

[0029]FIG. 8 is a view showing the upper surface of the display unit.

DETAILED DESCRIPTION OF THE INVENTION

[0030] A personal computer according to an embodiment of the presentinvention will be described below with reference to the views of theaccompanying drawing.

[0031]FIG. 1 is a perspective view of a notebook PC according to anembodiment of the present invention. As shown in FIG. 1, a notebook PC 1includes a personal computer body 2 and a display unit 3 rotatablymounted on the personal computer body 2 through hinges 4.

[0032] The display unit 3 has a display panel 5 and fuel cell assemblypanel 7. The fuel cell assembly panel 7 is placed in the housing of thedisplay unit 3, and hence is shown by the dotted lines. By placing thefuel cell assembly panel 7 in the housing of the display unit in thismanner, a large area for the fuel cell assembly panel can be ensured.

[0033] A drain hole 6 for draining water produced by the fuel cellassembly panel 7 is formed in a side wall of the housing of the displayunit 3 at the near end to the personal computer body 2.

[0034] During the notebook PC 1 is running, the display unit 3 of thenotebook PC 1 is generally kept near vertical. For this reason, aportion of the water produced in the fuel cell assembly panel 7 whichhas not vaporized and remained in the form of a liquid is gathered to alower portion by gravity.

[0035] This can therefore prevent insufficient ventilation due to thewater produced in the fuel cell assembly panel 7. When the user connectsa drain hose 8 to the drain hole 6, the water gathered to the lowerportion of the display unit 3 is discharged outside so as not to affectthe notebook PC 1. A tool other than the drain hose, e.g., a bottle forcollecting water, may be connected to the drain hole 6.

[0036] Although not shown in FIG. 1, the drain hole 6 has a drainagesensor for detecting that a drain tool, e.g., the above drain hose ordrain bottle, is connected to the drain hole 6.

[0037] Like conventional notebook PCs, this notebook PC can be poweredby a large power supply capacity using a detachable Li battery andreceive power through an AC adapter. In this case, as in the prior art,the notebook PC can perform high-speed, high-performance operation usinga power of several ten W level. When the fuel cell assembly is to beused, this notebook PC 1 operates in a specialized fuel cell assemblymode in which power consumption remains in a predetermined range by amethod to be described later.

[0038] A fuel cartridge 40 for supplying a fuel to a fuel cell assemblypanel 7 is mounted on the upper surface of the display unit 3. A throughhole 40 a is formed in this fuel cartridge 40 to prevent interferencewith the flow of air supplied to the fuel cell assembly panel 7 forsupplying air to the fuel cell assembly panel 7 mounted on the displayunit 3.

[0039] Although not shown in FIG. 1, a mesh-like member for preventinginsertion of undesirable object such as a pencil or stick may be mountedin the outlet/inlet of the through hole 40 a of the fuel cartridge 40.

[0040]FIG. 2 is a sectional view taken along a line X-X′ of the displayunit 3 of the notebook PC 1 in FIG. 1. The display unit 3 is rotatablyconnected to the personal computer body 2 through the hinges 4.

[0041] Referring to FIG. 2, reference numeral 30 denotes the housing ofthe display unit 3. In general, this housing is made of plastic or amagnesium alloy and serves to physically hold constituent elements inthe display unit 3 and protect them when, for example, the notebook PC 1is carried.

[0042] This housing 30 has an LCD panel 5. The internal structure of theLCD panel 5 is not shown in FIG. 2. At the level of the conceptualstructure described with reference to FIG. 2, the conventional displayunit 3 is comprised of the housing 30 and LCD panel 5.

[0043] In the notebook PC of this embodiment, the fuel cell assemblypanel 7 is mounted in the display unit 3, and a shield 32 is insertedbetween the LCD panel 5 and the fuel cell assembly panel 7.

[0044] The shield 32 is constituted by a metal plate 32A and heatinsulating layer 32B. The metal plate 32A may be a metal foil.

[0045] The metal plate 32A prevents electromagnetic waves generated fromthe LCD panel from being radiated outside. In a conventional notebookPC, the magnesium alloy of a housing itself or the plating on the innersurface of a plastic housing prevents unnecessary electromagnetic wavesradiated from the LCD panel from being radiated outside.

[0046] When the fuel cell assembly panel 7 is placed behind the rearsurface of the LCD panel 5, the metal plate 32A is preferably placedimmediately behind the LCD panel 5 to block unnecessary electromagneticwaves. This is because, the fuel cell assembly panel 7 requires air,resulting in difficulty in blocking electromagnetic waves. In addition,the shield 32 also serves to insulate the water produced in the fuelcell assembly panel 7 from the LCD panel 5.

[0047] The heat insulating layer 32B thermally insulates the LCD panel 5and fuel cell assembly panel 7. The fuel cell assembly panel 7 is heatedto a temperature higher than that in an operation environment forgeneral electronic equipment.

[0048] The LCD panel 5, especially an STN LCD, considerably deterioratesin contrast at a high temperature. Therefore, the heat resistancebetween the LCD panel 5 and the fuel cell assembly panel 7 must besufficiently high. The heat insulating layer 32B serves as a means forthis purpose.

[0049] An air supply channel 33 is formed between the shield 32 and thefuel cell assembly panel 7. The air supply channel 33 serves to supplyair to the fuel cell assembly panel 7, and is provided between theshield 32 and fuel cell assembly panel 7.

[0050] More specifically, the air supply channel 33 is formed into alaminar shape to supply air to the entire area of one surface of thefuel cell assembly panel 7. That is, the space between the shield 32 andfuel cell assembly panel 7 forms the air supply channel 33.

[0051] The reason why the air supply channel 33 of the fuel cellassembly panel 7 is formed near the LCD panel 5 is that the averagetemperature of the air supply channel 33 is generally lower than that ofa fuel supply channel 35, and the above heat insulation is facilitatedaccordingly.

[0052] The placement of the metal plate 32A between the heat insulatinglayer 32B and the LCD panel 5 reduces the temperature nonuniformity ofthe LCD panel 5, providing a good effect in the use of an STN LCD inparticular. Note that the shield 32 may be integrated with the LCD panel5.

[0053] Using the metal plate 32A instead of a metal foil improves safetyin some cases. The display unit 3 includes a light source for backlightas a component. In many cases, a relatively high voltage is applied tothis light source.

[0054] If this light source is integrated with the fuel cell assemblypanel 7, an accident may occur when the user carelessly inserts aconductive rod into an air inlet 41A of the fuel cell assembly panel 7.

[0055] By separating the fuel cell assembly panel 7 from the LCD panel 5using the metal plate 32A, the safety in such a case can be improved.Referring to FIG. 2, the LCD panel 5 has a flat shape. In actual design,however, the backlight light source and its power supply, in particular,do not have flat shapes in many cases.

[0056] In such a case, the metal plate 32A must be formed into a shapeother than a flat shape in accordance with the actual shapes of theabove components. Since such design is easy to make, a descriptionthereof will be omitted. That is, this apparatus may be shaped toeffectively insulate a portion where a high voltage is applied and aproblem may occur in terms of safety from the air inlet 41A for a fuelcell assembly.

[0057] For the sake of simplicity, FIG. 2 does not show the internalstructure of the fuel cell assembly panel 7. This fuel cell assemblypanel is a so-called DMFC designed to generate power by directlyoxidizing methyl alcohol.

[0058] Typically, therefore, in such a panel, a layer (anode) containingmethyl alcohol and water is formed one side of a solid-state polymericfilm through which hydrogen ions pass, and a layer (cathode) thatreceives air and oxidizes hydrogen ions is formed on the other side ofthe polymeric film.

[0059] For the above reason, the gap between the LCD panel 5 and theheat insulating layer 32B located near the LCD panel 5 is used as theair supply channel 33, and the gap between the housing and the fuel cellassembly is used as the fuel supply channel 35.

[0060] The fuel cartridge 40 is mounted on the upper portion of thedisplay unit 3. Although not shown in FIG. 1, the fuel cartridge 40serves to supply methyl alcohol as fuel to the fuel supply channel 35.

[0061] An air outlet 41B and the air inlet 41A are formed in an upperedge portion 36 and lower edge portion 37 of the housing 30 of thedisplay unit 3 to supply air to the fuel cell assembly. The area of theopening portion of each of the air inlet 41A and air outlet 41B is setto be larger than the area of the opening portion on the air supplychannel 33 side to become almost equal to the cross-sectional area ofthe air supply channel 33, thereby preventing blockage of an air flow.

[0062]FIG. 8 shows the upper surface portion of the display unit 3without the fuel cartridge 40. As shown in FIG. 8, a plurality of vents46 are formed in an opening portion of the air outlet 41B of the displayunit 3.

[0063] The display unit 3 of the notebook PC is generally kept open atan angle near the right angle during operation. In accordance with thisstate, the air supply channel 33 of the fuel cell assembly panel 7 drawsair through the air inlet 41A at the lower portion 37 of the housing 30of the display unit 3 by natural convection, supplies oxygen in the airto the fuel cell assembly panel 7, and exhausts air through the airoutlet 41B at the upper portion 36 of the housing 30.

[0064] During operation, the fuel cell assembly generates considerableheat (if the efficiency is 50%, the same amount of heat as thatgenerated in the notebook PC (the display panel including the backlightand the main body) is generated in the fuel cell assembly panel). Thethickness of the air supply channel 33 is minimized by using the chimneyeffect produced by this heat.

[0065] To facilitate the supply of oxygen to the fuel cell assemblypanel 7, the fuel panel may be inverted, and a hole may be formed in thehousing opposing the panel. In this case, however, the overall thicknessof the display unit 3 needs to be greatly increased to assure safety inconsideration of, for example, a case where the notebook PC collidesagainst an external projection while the user is carrying the PC.

[0066] In this embodiment, the thickness of the display unit 3 of thenotebook PC is considerably larger than that of the display unit of aconventional notebook PC. To prevent a further increase in thickness, noair inlet is preferably formed in the surface of the housing thatopposes the fuel cell assembly panel 7.

[0067] Note that FIG. 2 is a conceptual illustration, and hence does notshow the great differences between the heights of the upper and lowerportions 36 and 37 of the housing 30 and the thickness of the housingthat opposes the fuel cell assembly panel 7. It is widely known that theheights of the upper and lower portions 36 and 37 of the housing 30 ofthe conventional notebook PC are much larger than the thickness of thehousing.

[0068] Although ventilation based on a chimney effect can be expected,the air supply channel 33 must be designed to be wider than the fuelsupply channel 35. Fuel supply is mainly performed as transportation ofa liquid using wettability and capillarity. The fuel supply channel 35also serves as an exhaust channel for carbon dioxide gas produced byhydrolysis of methyl alcohol.

[0069] When, however, the overall thickness of the display unit is to bedecreased, the air supply channel 33 may be designed to be wider thanthe fuel supply channel 35. To prevent evaporation of methyl alcohol,the fuel supply channel 35 is preferably designed as a closed channelhaving an outlet for carbon dioxide gas.

[0070] More specifically, the lower end (corresponding to the portion37) of the fuel supply channel 35 is normally closed, and an openingthat is much smaller than a portion corresponding to the air supplychannel 33 is formed in the upper end portion of the fuel supply channel35 to discharge carbon dioxide (not shown)

[0071] As is known well, drying of the fuel cell assembly panel must beprevented while the fuel cell assembly is not used. Doors that are keptclosed while the fuel cell assembly is not used are attached to theupper and lower end gates of the air supply channel 33.

[0072] In addition, doors are provided for a drain outlet 5 and thecarbon oxide outlet to mainly prevent water in the fuel cell assemblyfrom dropping while the notebook PC is carried. These doors are notshown because they should be designed in accordance with individualsituations.

[0073] A drain member 38 is provided for the lower portion 37 of thehousing 30 to receive water produced by the fuel cell assembly panel 7and guide it to a hole 39 communicating with the drain hole 6 formed inthe side surface of the display unit 3. In this case, the shape of thedrain member 38 is designed to sufficiently ensure air supplied from theair inlet 41A to the fuel cell assembly panel 7 through the air supplychannel 33.

[0074] This drain member 38 receives water produced in the fuel cellassembly panel 7 and guides it to the hole 39. As a result, the water isdrained through the drain hole 6.

[0075]FIG. 3 is a block diagram of the notebook PC according to thisembodiment of the present invention. FIG. 3 shows only the constituentelements required to explain a fuel cell assembly mode to be describedlater, but does not show all the constituent elements of the notebookPC.

[0076] An AC adapter 5 is connected to a power supply input connector 10of the notebook PC 1. The power input from the display panel 5 isconverted into a voltage suitable for each portion in the notebook PC bya power supply portion 11, and applied to each portion.

[0077] As in the prior art, the power supply portion 11 is connected toa battery pack 12 so that it can charge the battery pack 12, and canreceive power from the battery pack 12 and supply it to each portion inthe notebook PC as described above.

[0078] One of the portions to which the power supply portion 11 suppliespower is a main board 13 of the notebook PC 1. The main board 13 has aCPU 14. FIG. 3 shows a modem 15 and DVD player/recorder 16 as examplesof peripheral devices connected to the main board 13.

[0079] The power output from the fuel cell assembly panel 7 mounted inthe display unit 3 is also input to the power supply portion 11. Anoutput from the sensor 9 described above is also input to the powersupply portion 11.

[0080] As in the prior art, the power supply portion 11 incorporates aDC/DC converter, power supply microcomputer, cell charge/dischargecontrol IC, and the like. Even while the notebook PC 1 is kept off, thepower supply microcomputer operates on low power to monitor events suchas pressing of the power switch of the notebook PC and supply of powerto the power supply input connector 10 as in the prior art.

[0081] One of the characteristic features of the power supplymicrocomputer according to the present invention is that an operationmode of using the fuel cell assembly is set when it is expected from theoperation of the drainage sensor 9 that water is properly drained fromthe fuel cell assembly panel 7, and the power supply voltage of the fuelcell assembly panel 7 falls within a predetermined voltage range.

[0082] Assume that the notebook PC is in the OFF state, and the drainagesensor 9 of the fuel cell assembly panel 7 is operating while the ACadapter 5 is not connected. In this case, when it is determined thatfuel is supplied to the fuel cell assembly panel 7, and the fuel cellassembly is set in the ON state, the fuel cell assembly mode is set.

[0083] Since an operation mode is automatically set in this manner, nomode setting error due to a user operation error occurs.

[0084] The fuel cell assembly mode will be described in detail next.

[0085] In the fuel cell assembly mode, the power consumption during theoperation of the notebook PC 1 is reduced to allow the notebook PC 1 tooperate on the power supplied from the fuel cell assembly.

[0086] Although several methods of reducing power consumption areconceivable, typical methods will be described below. Obviously, anymethod of reducing power consumption, other the following methods, maybe used, and some of the methods to be described below may be combined.

[0087] The first example is a method of setting the CPU in a low powerconsumption mode (step S11) when the current operation mode is switchedto the fuel cell assembly mode. Since the technique of allowing the CPUto operate in the low power consumption mode is a well known technique,a detailed description thereof will be omitted. A recent CPU is designedwith the principal emphasis being placed on a reduction in powerconsumption at a high operation speed. For this reason, in some cases,the power supply voltage applied to the core in the CPU chip isminimized, and leakage currents from the transistors increase. In such acase, in the fuel cell assembly mode of greatly decreasing the clockrate, the power consumption may be reduced by slightly increasing thepower supply voltage to the core as compared with the normal mode. As isknown, in the normal mode, the power consumption is reduced bydecreasing the power supply voltage to the core.

[0088] The CPU architecture also preferably has the low powerconsumption mode. For example, to increase the degree of parallelprocessing, a recent CPU obtains a result as if a plurality ofinstructions designated for serial execution on the program wereexecuted in parallel and the results were serially output without anyinconsistency. In the fuel cell assembly mode, the power consumption ispreferably reduced by a design for simply serially executing commandswithout supplying the power to a circuit for such parallel processing.

[0089] In the second example, applications, which cannot be executed inthe fuel cell assembly mode or are inappropriate to execute in the fuelcell assembly mode, are not executed.

[0090] More specifically, as shown in FIG. 5, the user designates inadvance applications which cannot be executed in the fuel cell assemblymode or are inappropriate to execute in the fuel cell assembly mode(S12).

[0091] In this case, the user designates the applications in advance.However, the applications may be automatically detected by software ordesignated in advance at the time of shipment from a factory. Thedesignated applications are disabled to inhibit the start (S13).

[0092] In this embodiment, traditional office applications (e.g., WORD)and Internet accesses using the modem 15 can operate (moving image ormusic application cannot operate, as described above). Theseapplications can be practically executed even by a CPU with considerablylow performance and are also determined as applications whose needs forlong-time use outdoor are high.

[0093] In the third example, some peripheral devices are not activated.

[0094] More specifically, as shown in FIG. 6, some peripheral devicesare disabled (S21). In this embodiment, the DVD player/recorder 16 isnot activated in the fuel cell assembly mode. This is because the DVDplayer/recorder 16 itself requires high power consumption, and a movingimage as a main application that uses the DVD player/recorder 16requires full use of CPU performance and therefore real-time processingcannot be executed by the CPU in the low power consumption mode.

[0095] In the fuel cell assembly mode, the battery pack 12 is notcharged or discharged (is not used as a power supply). This is because,in the fuel cell assembly mode, the operation of the PC cannot relay onthe battery pack 12. The user is required to understand this point inusing the PC. In addition, this operation is inhibited to avoid theundesired operation of charging the battery with a low voltage from thefuel cell assembly.

[0096] Switching between the fuel cell assembly mode and the normal modeis performed only when the notebook PC is in the OFF state. Thisfacilitates switching to the low power consumption mode at the CPUarchitecture level. This operation is also important from the viewpointof the prevention of a user operation error.

[0097] If fuel is fed into the fuel cell assembly of the notebook PC 1which is operating in the normal mode, a warning message is displayed onthe screen, and the notebook PC 1 keeps operating in the normal mode inthis embodiment. This eliminates ambiguity in interpreting the fuel cellassembly mode, and hence prevents a contradiction between userexpectations and the operation of the notebook PC 1.

[0098]FIG. 7 is a state transition chart for explaining mode switchingoperation for the notebook PC according to this embodiment. Morespecifically, in this embodiment, this operation is implemented asfirmware of the power supply control microcomputer.

[0099] A state 50 is an initial state. Overall power supply control forthe conventional notebook PC is included in a frame 54. This control canbe basically used as part of this embodiment of the present inventionwithout any change, and hence a detailed illustration thereof is omittedin FIG. 7.

[0100] The state 50 is equivalent to the OFF state in the prior art, inwhich each processing sequence is started in accordance with an eventsuch as turning on the power SW, meeting a resume condition, or meetingWake On LAN condition.

[0101] A series of operations to be executed when the power switch isturned on are shown as states 51 to 53 altogether. In this case, FIG. 7shows the power ON sequence 51, operation sequence 52, and power OFFsequence 53.

[0102] The state 50 is the only neutral state which allows switchingbetween the fuel cell assembly mode and the normal mode in thisembodiment. If a drain pipe or water collecting unit is connected to thedrain hole 6 of the fuel cell assembly (FC) in this state, the currentmode switches to an OFF state 55 as the fuel cell assembly mode. In thiscase, the drainage sensor 9 shown in FIG. 3 detects the connection ofthe drain pipe or water collecting unit to the drain hole 6.

[0103] If the power switch is turned on, the notebook PC is started inthe fuel cell assembly mode. Unlike the normal mode such as an Libattery driving mode, a sequence 56 of starting the fuel cell assemblyis executed before the start of the power supply ON sequence for thenotebook PC.

[0104] Since the manner of starting the fuel cell assembly greatlyvaries depending on the design of a fuel cell assembly unit, a detaileddescription of this sequence will be omitted. In general, in this step,the temperature of the fuel cell assembly is raised, and the fuel cellassembly is connected to a built-in dummy load to increase the output ofthe fuel cell assembly to a predetermined value.

[0105] This operation is performed because the load response speed ofthe fuel cell assembly is generally very low. When a large loadvariation occurs, it may take a time of about 1 sec before thestabilization of a current. If, therefore, the notebook PC is directlystarted by using a fuel cell assembly without no load, sufficient powercannot be supplied.

[0106] When the output of the fuel cell assembly becomes sufficientlyhigh, the power supply microcomputer executes a power supply ON sequence56 for the notebook PC. This sequence is essentially the same as thepower supply ON sequence 51 in the prior art, but slightly variesdepending on the form of the fuel cell assembly mode. If, for example, apredetermined peripheral device is disabled, the number of components towhich power should be supplied decreases. In this sense, this sequenceis the power supply ON sequence unique to the fuel cell assembly mode.

[0107] Since the subsequent operation in the fuel cell assembly mode isalmost the same as that in the normal mode, a description thereof willbe omitted. The operation in a frame 61 in FIG. 7 corresponds to a statewhere the notebook PC is set in the fuel cell assembly mode. In thismode, while the notebook PC is operating, mode switching is inhibited.

[0108] Mode switching is allowed only after the notebook PC is turnedoff, and its state shifts to the state 55. Likewise, while the notebookPC is in the normal mode, i.e., in the state enclosed with the frame 54,switching to the fuel cell assembly mode is inhibited. During the normalmode, power input from the fuel cell assembly is disconnected by aswitch in the power supply portion 11.

[0109] Even if, therefore, the user feeds fuel into the fuel cellassembly during the operation of the notebook PC on the battery, thefuel cell assembly is substantially kept in the disconnected state atthis time. The current mode switches to the fuel cell assembly modethrough the neutral mode only after the user turns off the notebook PC.

[0110] In the state 55, in which an drain means is connected to the fuelcell assembly, and the notebook PC is in the OFF state, if, for example,a condition for Wake On LAN is satisfied, the notebook PC operates inthe same manner as in a case where the condition is satisfied in theneutral mode.

[0111] More specifically, the notebook PC is started by using thebattery as a power supply, and processing for Wake On LAN is started. Inthis case, since the normal mode is set, power from the fuel cellassembly is disconnected.

[0112] According to the notebook PC of this embodiment, therefore, bymounting a single-panel type fuel cell assembly, which is easier tomanufacture, in the display unit of the notebook PC, a fuel cellassembly panel having a size similar to that of the display unit of thenotebook PC can be used. As a consequence, high power can be supplied tothe notebook PC as compared with the conventional notebook PC.

[0113] According to this embodiment, since a drain unit is connected tothe drain hole, and the operation mode is automatically switched to thefuel cell assembly mode only when the notebook PC is in the OFF state,no mode setting error based on the misunderstanding of the user occurs.

[0114] The implementation of the fuel cell assembly mode can prevent theuse of the notebook PC beyond the capacity of the fuel cell assembly.

[0115] In addition, in this embodiment, in the fuel cell assembly mode,the built-in secondary battery is not charged/discharged. This reliablymakes the user understand that he/she cannot relay on the built-insecondary battery in the fuel cell assembly mode.

[0116] As described in detail above, according to the present invention,there is provided an electronic apparatus which can incorporate a fuelcell assembly panel having a large area, and provides good ventilationfor the fuel cell assembly panel. In addition, an electronic apparatuswhich can properly operate even at a low output obtained from a fuelcell assembly can be provided.

[0117] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. An electronic apparatus comprising: a displayunit having a display panel; a fuel cell assembly arranged in thedisplay unit, which supplies power to said electronic apparatus; and anair channel, arranged in the display unit, which supplies air to saidfuel cell assembly.
 2. The apparatus according to claim 1, furthercomprising a shield, located between said fuel cell assembly and saiddisplay panel, configured to prevent conduction of heat generated bysaid fuel cell assembly to said display panel.
 3. The apparatusaccording to claim 1, further comprising a shield, located between saidfuel cell assembly and said display panel, configured to prevent afailure caused by electromagnetic waves generated by said display panel.4. The apparatus according to claim 1, further comprising a shield,located between said fuel cell assembly and said display panel,configured to prevent water produced by said fuel cell assembly fromentering said display panel.
 5. The apparatus according to claim 2,wherein a drain hole for draining water produced by said fuel cellassembly is formed in a side surface of said display unit.
 6. Theapparatus according to claim 3, wherein a drain hole for draining waterproduced by said fuel cell assembly is formed in a side surface of saiddisplay unit.
 7. The apparatus according to claim 4, wherein a drainhole for draining water produced by said fuel cell assembly is formed ina side surface of said display unit.
 8. The apparatus according to claim5, wherein said apparatus further comprises a sensor for detecting thata drain unit is connected to the drain hole, and said fuel cell assemblyis used when said sensor detects that the drain unit is connected to thedrain hole.
 9. The apparatus according to claim 6, wherein saidapparatus further comprises a sensor for detecting that a drain unit isconnected to the drain hole, and said fuel cell assembly is used whensaid sensor detects that the drain unit is connected to the drain hole.10. The apparatus according to claim 7, wherein said apparatus furthercomprises a sensor for detecting that a drain unit is connected to thedrain hole, and said fuel cell assembly is used when said sensor detectsthat the drain unit is connected to the drain hole.
 11. The apparatusaccording to claim 2, wherein the air channel is formed between saidfuel cell assembly and said shield, and vents are formed in bottom andupper surfaces of said display panel.
 12. The apparatus according toclaim 3, wherein the air channel is formed between said fuel cellassembly and said shield, and vents are formed in bottom and uppersurfaces of said display panel.
 13. The apparatus according to claim 4,wherein the air channel is formed between said fuel cell assembly andsaid shield, and vents are formed in bottom and upper surfaces of saiddisplay panel.
 14. The apparatus according to claim 11, wherein a fuelsupply channel for supplying fuel to said fuel cell assembly is formedbetween said fuel cell assembly and said display unit, and across-sectional area of the air supply channel is larger than that ofthe fuel supply channel.
 15. The apparatus according to claim 12,wherein a fuel supply channel for supplying a fuel to said fuel cellassembly is formed between said fuel cell assembly and said displayunit, and a cross-sectional area of the air supply channel is largerthan that of the fuel supply channel.
 16. The apparatus according toclaim 13, wherein a fuel supply channel for supplying a fuel to saidfuel cell assembly is formed between said fuel cell assembly and saiddisplay unit, and a cross-sectional area of the air supply channel islarger than that of the fuel supply channel.
 17. The apparatus accordingto claim 5, further comprising: a detection unit detecting that a toolfor collecting water produced by said fuel cell assembly is connected tothe drain hole; and a unit causing the apparatus operate in a lowconsumption power of using said fuel cell assembly as a power supplywhen said detection unit detects that the tool is connected to the drainhole, and a power supply of said electronic apparatus is in an OFFstate.
 18. The apparatus according to claim 6, further comprising: adetection unit detecting that a tool for collecting water produced bysaid fuel cell assembly is connected to the drain hole; and a unitcausing the apparatus operate in a low consumption power of using saidfuel cell assembly as a power supply when said detection unit detectsthat the tool is connected to the drain hole, and a power supply of saidelectronic apparatus is in an OFF state.
 19. The apparatus according toclaim 7, further comprising: a detection unit detecting that a tool forcollecting water produced by said fuel cell assembly is connected to thedrain hole; and a unit causing the apparatus operate in a lowconsumption power of using said fuel cell assembly as a power supplywhen said detection unit detects that the tool is connected to the drainhole, and a power supply of said electronic apparatus is in an OFFstate.
 20. A method of driving an electronic apparatus including anelectronic apparatus body, and a display unit rotatably mounted on theelectronic apparatus body, the display unit having a fuel cell assemblyfor supplying power to the electronic apparatus and a drain hole fordraining water produced by the fuel cell assembly, comprising: detectingthat a tool for collecting water produced by the fuel cell assembly isconnected to the drain hole and a power supply of the electronicapparatus is in an OFF state; switching to a fuel cell assembly mode forusing the fuel cell assembly, when it is detected that a tool forcollecting water produced by the fuel cell assembly is connected to thedrain hole, and a power supply of the electronic apparatus is in an OFFstate; and executing a power supply ON sequence unique to the fuel cellassembly mode when the power supply of the electronic apparatus isturned on, and a power of the fuel cell assembly reaches a predeterminedoutput value.
 21. The method according to claim 20, wherein theapparatus operates in a low power consumption mode in the fuel cellassembly mode.
 22. The method according to claim 20, wherein apredetermined application program is executed in the fuel cell assemblymode.
 23. An apparatus according to claim 20, wherein a predeterminedperipheral device is driven in the fuel cell assembly mode.
 24. Anelectronic apparatus comprising: a display panel provided in a displayunit; a fuel cell assembly arranged in parallel with the display panel;an air channel which is arranged between the display panel and fuel cellassembly such that the air channel faces the fuel cell assembly andwhich has openings at upper and lower end portions of the display unit,respectively; and a shield, arranged between the air channel and displaypanel, configured to shield the display panel from water generated bythe fuel cell assembly.
 25. The apparatus according to claim 24, whereinthe shield is configured to shield the fuel cell assembly from anelectromagnetic wave generated from the display panel.
 26. The apparatusaccording to claim 24, wherein the display unit has a drain hole, whichis formed at lower portion of the display unit, configured to drainwater produced from said fuel cell assembly.